Over the past months, a small-scale field study has been carried out at 3 study sites: Braddell Heights, Tampines West and Nee Soon East, to understand the behaviour of male Wolbachia-Aedes aegypti mosquitoes in our urban built-up environment.

The study has yielded valuable data on how far and high the male mosquitoes fly (horizontal and vertical dispersal), how long they live (longevity), and how well they compete in the urban environment (mating competitiveness). This information is critical to guide design of the subsequent suppression trial.

a) How far and high they fly

Horizontal Dispersal

Early findings gathered from the Braddell Heights study site showed that the majority (90%) of male Wolbachia-Aedes was caught within 40m from the release point.

Vertical Dispersal

When released on the ground level, the male Wolbachia-Aedes are able to fly up to higher levels, even to the top.

b) How long they live

Early findings gathered at the Braddell Heights and Nee Soon East study sites showed that the majority of male Wolbachia-Aedes caught were within 7 days post-release. Using mathematical modelling, it is estimated that 50% of the male Wolbachia-Aedes survived to 4 days after release.

c) How well they compete in the urban environment

Following three months of releases at the Tampines West study site, the viability of Aedes aegypti mosquito eggs collected from the site has been reduced by about half, suggesting that the released male Wolbachia-Aedes  successfully mated with the urban Aedes aegypti females.